This invention relates generally to touch fasteners, and specifically to touch fasteners for engaging fibers and to methods and apparatus for their manufacture.
There has been much development over the last thirty years in the field of hook-and-loop fasteners. Early touch fastener products of this type consisted of two mating tapes, each being knit or woven. One tape would include loops of filament woven into a base, and the other would include filaments woven to form loops and then cut to form hooks. In some cases free ends of drawn plastic filaments on the male tape would be melted to form protruding heads. This shape of fastener element is sometimes called a “mushroom”, to distinguish it from “hook”-shaped elements with re-entrant crooks.
More recently, continuous molding of fastener elements extending from a common sheet-form resin base has resulted in less expensive and thinner male tapes. Significant improvements in this area include the development of continuous fastener tape molding using fixed mold cavities (see Fischer, U.S. Pat. No. 4,794,028), and the ability to provide loops on the back side of the male fastener tape as the fastener tape substrate and elements are being formed (see Kennedy et al., U.S. Pat. No. 5,260,015), thus creating a composite fastener tape capable of fastening to itself.
Much recent development has been directed at making smaller fastener elements in dense arrays for engaging low-loft non-wovens and inexpensive, lightweight knits for disposable garments and such. It is now common to mold look-shaped fastener elements as short as 0.015 inch, or smaller.
Generally, male fastener elements are designed to engage stable loops or fibers (i.e., loops or fiber sections extending between two fixed ends). As discussed below, there is a need or desire for a releasable fastener capable of engaging a fibrous substrate.